A general indication as to the use of a robot by means of which the removal process of plastic bags in stacks from a bag-making and stacking unit can be automated in a receiving station can be found in DE 38 34 115 C1. However in this case the known device is based on the assumption that the individual bags are kept together in the bag stack by using wire brackets. Details regarding the use of the robot in the removal of the plastic bags cannot be found in this reference.
Moreover the reference indicates generally that the use of a robot has so far not developed due to its complexity and high cost.
It is also generally known to eliminate the use of wire brackets for keeping the individual plastic bags together in the bag stack during stack removal. An interlocking of the individual plastic bags into a bag stack can take place in the pin stacking conveyor, because the plastic bags can be fused together by pressure and heat in certain areas, for instance in an area defined by a perforation line. In this way a considerable simplification of the production of plastic bags is achieved, since also the removal of the bag stacks from the pin stacking conveyor is considerably improved and also the packaging of the plastic bags in boxes or the like is noticeably simplified.
However it is up to the operator to watch over the quality of the interlocked bag packages and to prepare their packaging for instance in a cardboard box. These preparations for the packaging in a box creates difficulties especially in the case of plastic bags with a bottom fold. This happens especially because in the stack the plastic bags with bottom fold lying on top of each other build up quicker in the bottom folds area which thicker than in the flat top areas.
Depending on the kind and size of the bag, the bottom areas are inclined to turn over, when the bag package comes to lie in a horizontal or approximately horizontal position. Therefore even with the use of a robot an operator is kept pretty busy in order to produce perfect bag packages. However this is achieved only when the production speed is reduced, so that the delivery machine operator can follow the package preparation.